Authors: Motov S et al., Am J Emerg Med 2017 Mar 3;
Neuropsychiatric side effects were more common with intravenous push administration, but does it matter?
At intravenous (IV) doses of 0.1–0.3 mg/kg, ketamine is a safe and effective analgesic. Adverse effects are minimal and include sedation and a feeling of disconnection from reality. Investigators compared the effectiveness and adverse effect burden of ketamine administration by IV push versus slow infusion in a randomized, placebo-controlled, double-dummy trial.
Forty-eight emergency department patients with acute pain received 0.3 mg/kg of IV ketamine given either over 5 minutes by push or over 15 minutes by infusion. Feelings of unreality (quantified using the Side Effects Rating Scale for Dissociative Anesthetics) were more common in the IV push group overall (92% vs. 54%). Sedation was more pronounced in the IV push group, with median Richmond Agitation-Sedation Scale values at 5 minutes of −2 versus 0. The groups were comparable in terms of analgesic efficacy, but feelings of unreality were more pronounced in the IV push route at all time points.
This well-conducted study suggests that analgesic-dose ketamine causes less dissociation and sedation when infused over 15 minutes than when pushed over 5 minutes.